I hate reading about this kind of very easily avoidable cat attack.
Are there any penetration wounds anywhere on the dragon's body (from fangs or claws) ?
VERY BAD if this the case . If the vet was a good one , he will have started the little dragon off on both oral and injectable very broad spectrum antibiotics , and a long course of these will be required for the dragon to stand a chance of surviving.
Did the vet check for broken bones AND internal bleeding (Xrays) ?
Very high risk of internal bleeding from damaged internal organs (cats throw their victims about very violently and jump ontop of them (imagine the effect of an elephant stamping on a child , very similar effect), only time will tell if there are ruptures to the lungs, the liver, the kidneys, the gastro intestinal track , internal bleeding will have shown up in xrays if taken.
If you are very lucky, the cat didn't maul or bite the dragon and didn't have time to inflict any internal organ or bone damage. I which case the dragon is in shock and has been traumatized by it's experience but will eventually come good ( if it's still sick tomorrow , my advise is taking it back to the vet as a matter of URGENCY ).
CAT IN THE HOUSE / YARD
Personally - I'd be getting rid of the cat. They are hardwired hunters / killers and torture the animals they catch for the fun of it , and are very sneaky and determined once they know there is lizard in the house.
Now the cat knows there is a lizard in the house you will find it impossible to keep the lizard safe unless you make the dragon's tank cat proof and the cat is banished to a cage when ever the dragon comes out it's tank (assuming it survives the trauma and doesn't die from a very nasty systemic infection due to the germs on the cats fangs, claws and in it's saliva).
I have lost count of the number of times I've warned here and elsewhere that tanks with mesh lids are NOT CAT PROOF and warned about cats living in the same home as pet lizards (and how it inevitably ends nastily for the lizard).
If you can't part with the cat , the lizard tank MUST have the mesh top removed permanently and it made cat proof , you can not train a cat to leave a lizard alone or to stay away from it's tank , the cat will only stay away when you are looking , and will be back to stalking it and trying to get at it the moment you leave the room , simply moving the lizard tank to a room that you think you will exclude the cat from will not work , it only takes a moment of forgetfulness (someone leaves a door or window open enough for the cat to get in, or cat follows them unseen into the room).
There are four options for housing your dragon SAFELY from here forward :
option 1 : convert existing tank to a solid timber hinged lid
viewtopic.php?f=75&t=240221&p=1840683#p1840683
option 2 : convert existing tank by turning tank on it's side and turn the top into the front and add sliding glass (lockable) doors
viewtopic.php?f=34&t=246739
option 3 : move the dragon into a tub with a click clak style lid that has been modified , a 120L tub will be ideal for a juvenile up til it's first birthday ie
https://www.bunnings.com.au/all-set-120l-plastic-storage-container_p2583852 , conversion is easy and quick
, and the latches that hold the lid on will make it cat proof ie
viewtopic.php?f=34&t=233480
option 4 : invest in a solid timber front opening tank or build one for the dragon.